Abstract: A device for the metering of fluidizable bulk materials, having a storage tank and a mass-flow-measuring device for the material and a fluidizing device, which is connected to the storage tank via an aperture of adjustable size, and a control valve for controlling the supply of compressed air to the fluidizing device, wherein a pressure gauge is provided downstream of the fluidizing device, in the direction of flow, and the pressure gauge and control valve are connected via a first control circuit, and the supply of compressed air to the fluidizing device is metered by this control circuit in such a manner that a constant, in each case preselectable subatmospheric pressure prevails in the fluidizing device, and the mass-flow-measuring device and the aperture of adjustable size are connected via a second control circuit, and the size of the adjustable aperture is set by this control circuit in such a manner that a defined quantity of bulk material enters the fluidizing device.

Abstract: The invention relates to a method for preparing homogeneous dispersions of fluidizable bulk materials, wherein, in a first step, fluidizable bulk materials are blended with liquid to produce a raw dispersion and, in a second step, the raw dispersion is conveyed through a continuous enclosed dispersing apparatus by means of a forced-conveyance apparatus.

Abstract: A method for increasing the bulk weight of silicon dioxide with a surface of at least 50m.sup.2 /g by means of sub-atmospheric pressure applied at a filter face, wherein the silicon dioxide is moved by means of a conveyor screw, whose longitudinal axis is arranged parallel with respect to the filter face and which preferably has a decreasing thread pitch in feeding direction. Furthermore, the invention relates to the use of the treated silicon dioxide as a filler material for polymeric masses, especially diorganopolysiloxane, which is storeable in the absence of water and when admixed with water at room temperature results in a hardened elastomer mass.